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[PATCH] Fix printing of floating point numbers in objdump
- From: Andreas Schwab <schwab at linux-m68k dot org>
- To: binutils at sourceware dot org
- Date: Sat, 11 Aug 2012 16:17:30 +0200
- Subject: [PATCH] Fix printing of floating point numbers in objdump
floatformat_to_double mishandles floating point numbers between 1 and 2
(ie. with zero unbiased exponent) for floating point formats with more
then 32 mantissa bits: the bits beyond the first 32 are not correctly
shifted.
I have also simplified the handling of denormal numbers. The special
case can be reduced to setting the exponent to the minimum and assuming
a zero integer bit.
Andreas.
binutils/
* binutils-all/m68k/objdump.exp: Add flonum test.
* binutils-all/m68k/flonum.s: New file.
libiberty/
* floatformat.c (floatformat_to_double): Correctly handle numbers
between 1 and 2. Simplify handling of denormal number.
diff --git a/binutils/testsuite/binutils-all/m68k/flonum.s b/binutils/testsuite/binutils-all/m68k/flonum.s
new file mode 100644
index 0000000..22e92bb
--- /dev/null
+++ b/binutils/testsuite/binutils-all/m68k/flonum.s
@@ -0,0 +1,2 @@
+ fmove.d #0r1.1,%fp0
+ fmove.d #0r1e-310,%fp0
diff --git a/binutils/testsuite/binutils-all/m68k/objdump.exp b/binutils/testsuite/binutils-all/m68k/objdump.exp
index 5043ef7..e0b1d29 100644
--- a/binutils/testsuite/binutils-all/m68k/objdump.exp
+++ b/binutils/testsuite/binutils-all/m68k/objdump.exp
@@ -77,3 +77,35 @@ if [regexp $want $got] then {
} else {
fail "fnop test"
}
+
+#############################
+# Set up the test of flonum.s
+#############################
+
+if {![binutils_assemble $srcdir/$subdir/flonum.s tmpdir/flonum.o]} then {
+ return
+}
+
+if [is_remote host] {
+ set objfile [remote_download host tmpdir/flonum.o]
+} else {
+ set objfile tmpdir/flonum.o
+}
+
+# Test printing of floating point numbers
+
+set got [binutils_run $OBJDUMP "$OBJDUMPFLAGS --disassemble $objfile"]
+
+set want1 "0:\[ \t\]+f23c 5400 3ff1\[ \t\]+fmoved #0e1\\.1,%fp0"
+set want2 "c:\[ \t\]+f23c 5400 0000\[ \t\]+fmoved #0e1e-310,%fp0"
+
+if [regexp $want1 $got] then {
+ pass "flonum test 1"
+} else {
+ fail "flonum test 1"
+}
+if [regexp $want2 $got] then {
+ pass "flonum test 2"
+} else {
+ fail "flonum test 2"
+}
diff --git a/libiberty/floatformat.c b/libiberty/floatformat.c
index 1116c63..4e762d0 100644
--- a/libiberty/floatformat.c
+++ b/libiberty/floatformat.c
@@ -1,5 +1,5 @@
/* IEEE floating point support routines, for GDB, the GNU Debugger.
- Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006, 2010
+ Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006, 2010, 2012
Free Software Foundation, Inc.
This file is part of GDB.
@@ -503,20 +503,20 @@ floatformat_to_double (const struct floatformat *fmt,
mant_off = fmt->man_start;
dto = 0.0;
- special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
-
- /* Don't bias zero's, denorms or NaNs. */
- if (!special_exponent)
- exponent -= fmt->exp_bias;
-
/* Build the result algebraically. Might go infinite, underflow, etc;
who cares. */
- /* If this format uses a hidden bit, explicitly add it in now. Otherwise,
- increment the exponent by one to account for the integer bit. */
-
- if (!special_exponent)
+ /* For denorms use minimum exponent. */
+ if (exponent == 0)
+ exponent = 1 - fmt->exp_bias;
+ else
{
+ exponent -= fmt->exp_bias;
+
+ /* If this format uses a hidden bit, explicitly add it in now.
+ Otherwise, increment the exponent by one to account for the
+ integer bit. */
+
if (fmt->intbit == floatformat_intbit_no)
dto = ldexp (1.0, exponent);
else
@@ -530,18 +530,8 @@ floatformat_to_double (const struct floatformat *fmt,
mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits);
- /* Handle denormalized numbers. FIXME: What should we do for
- non-IEEE formats? */
- if (special_exponent && exponent == 0 && mant != 0)
- dto += ldexp ((double)mant,
- (- fmt->exp_bias
- - mant_bits
- - (mant_off - fmt->man_start)
- + 1));
- else
- dto += ldexp ((double)mant, exponent - mant_bits);
- if (exponent != 0)
- exponent -= mant_bits;
+ dto += ldexp ((double) mant, exponent - mant_bits);
+ exponent -= mant_bits;
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
--
1.7.11.4
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."